package com.mars.office.utils;

import java.io.ByteArrayOutputStream;
import java.io.UnsupportedEncodingException;

/**
 * Base64加解密
 * 
 * @author Administrator
 * 
 */
public class Base64Util {
	 private static char[] base64EncodeChars = new char[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',  
	        'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o',  
	        'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/' };  

	private static byte[] base64DecodeChars = new byte[] { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  
	        -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63, 52, 53, 54, 55,  
	        56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,  
	        21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46,  
	        47, 48, 49, 50, 51, -1, -1, -1, -1, -1 };  


	public static String encode(byte[] data)  
	{  
	    StringBuffer sb = new StringBuffer();  
	    int len = data.length;  
	    int i = 0;  
	    int b1, b2, b3;  

	    while (i < len)  
	    {  
	        b1 = data[i++] & 0xff;  
	        if (i == len)  
	        {  
	            sb.append(base64EncodeChars[b1 >>> 2]);  
	            sb.append(base64EncodeChars[(b1 & 0x3) << 4]);  
	            sb.append("==");  
	            break;  
	        }  
	        b2 = data[i++] & 0xff;  
	        if (i == len)  
	        {  
	            sb.append(base64EncodeChars[b1 >>> 2]);  
	            sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);  
	            sb.append(base64EncodeChars[(b2 & 0x0f) << 2]);  
	            sb.append("=");  
	            break;  
	        }  
	        b3 = data[i++] & 0xff;  
	        sb.append(base64EncodeChars[b1 >>> 2]);  
	        sb.append(base64EncodeChars[((b1 & 0x03) << 4) | ((b2 & 0xf0) >>> 4)]);  
	        sb.append(base64EncodeChars[((b2 & 0x0f) << 2) | ((b3 & 0xc0) >>> 6)]);  
	        sb.append(base64EncodeChars[b3 & 0x3f]);  
	    }  
	    return sb.toString();  
	}  

	public static byte[] decode(String str)  
	{  
	    byte[] data=new byte[0];
	    if (str==null) {
	    	return new byte[0];
	    }
		try {
			data = str.getBytes("utf-8");
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	    int len = data.length;  
	    ByteArrayOutputStream buf = new ByteArrayOutputStream(len);  
	    int i = 0;  
	    int b1, b2, b3, b4;  

	    while (i < len)  
	    {  

	        /* b1 */  
	        do  
	        {  
	            b1 = base64DecodeChars[data[i++]];  
	        }  
	        while (i < len && b1 == -1);  
	        if (b1 == -1)  
	        {  
	            break;  
	        }  

	        /* b2 */  
	        do  
	        {  
	            b2 = base64DecodeChars[data[i++]];  
	        }  
	        while (i < len && b2 == -1);  
	        if (b2 == -1)  
	        {  
	            break;  
	        }  
	        buf.write((int) ((b1 << 2) | ((b2 & 0x30) >>> 4)));  

	        /* b3 */  
	        do  
	        {  
	            b3 = data[i++];  
	            if (b3 == 61)  
	            {  
	                return buf.toByteArray();  
	            }  
	            b3 = base64DecodeChars[b3];  
	        }  
	        while (i < len && b3 == -1);  
	        if (b3 == -1)  
	        {  
	            break;  
	        }  
	        buf.write((int) (((b2 & 0x0f) << 4) | ((b3 & 0x3c) >>> 2)));  

	        /* b4 */  
	        do  
	        {  
	            b4 = data[i++];  
	            if (b4 == 61)  
	            {  
	                return buf.toByteArray();  
	            }  
	            b4 = base64DecodeChars[b4];  
	        }  
	        while (i < len && b4 == -1);  
	        if (b4 == -1)  
	        {  
	            break;  
	        }  
	        buf.write((int) (((b3 & 0x03) << 6) | b4));  
	    }  
	    return buf.toByteArray();  
	}  

	public static void main(String[] args) throws UnsupportedEncodingException {

		String testStr = "一二三";
		System.out.println("加密前：" + testStr);

		String encodeStr = Base64Util.encode(testStr.getBytes("utf-8"));
		System.out.println("加密数据：" + encodeStr);

		byte[] decodeStr = Base64Util.decode(encodeStr);
		System.out.println("解密数据：" + new String(decodeStr,"utf-8"));
		
		System.out.println(new sun.misc.BASE64Encoder().encode(testStr.getBytes()));
		
		
	}
}
